Maryland Code, Tax-Property § 14-808

(a)(1) Except for property that has been transferred by a municipality or county to a land bank authority established under § 1-1403 of the Local Government Article, and except as provided under § 14-811 of this subtitle, the collector shall proceed to sell and shall sell under this subtitle, at the time required by local law, all property in the county in which the collector is elected or appointed on which the tax is in arrears.

(2) Failure of the collector to sell within the time required by local law does not affect the validity or collectability of any tax, or the validity of any sale thereafter made.